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Former-commit-id:06a8b51d6d[formerly 64fa9254b946eae7e61bbc3f513b7c3696c4f54f] Former-commit-id:9f19e3f712
135 lines
3.8 KiB
ReStructuredText
Executable file
135 lines
3.8 KiB
ReStructuredText
Executable file
===============
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HTTP Exceptions
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===============
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.. automodule:: werkzeug.exceptions
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Error Classes
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=============
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The following error classes exist in Werkzeug:
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.. autoexception:: BadRequest
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.. autoexception:: Unauthorized
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.. autoexception:: Forbidden
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.. autoexception:: NotFound
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.. autoexception:: MethodNotAllowed
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.. autoexception:: NotAcceptable
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.. autoexception:: RequestTimeout
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.. autoexception:: Gone
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.. autoexception:: LengthRequired
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.. autoexception:: PreconditionFailed
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.. autoexception:: RequestEntityTooLarge
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.. autoexception:: RequestURITooLarge
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.. autoexception:: UnsupportedMediaType
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.. autoexception:: InternalServerError
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.. autoexception:: NotImplemented
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.. autoexception:: BadGateway
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.. autoexception:: ServiceUnavailable
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.. exception:: HTTPUnicodeError
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This exception is used to signal unicode decode errors of request
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data. For more information see the :ref:`unicode` chapter.
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Baseclass
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=========
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All the exceptions implement this common interface:
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.. autoexception:: HTTPException
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:members: get_response, __call__
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Special HTTP Exceptions
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=======================
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Starting with Werkzeug 0.3 some of the builtin classes raise exceptions that
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look like regular python exceptions (eg :exc:`KeyError`) but are
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:exc:`BadRequest` HTTP exceptions at the same time. This decision was made
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to simplify a common pattern where you want to abort if the client tampered
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with the submitted form data in a way that the application can't recover
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properly and should abort with ``400 BAD REQUEST``.
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Assuming the application catches all HTTP exceptions and reacts to them
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properly a view function could do the following savely and doesn't have to
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check if the keys exist::
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def new_post(request):
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post = Post(title=request.form['title'], body=request.form['body'])
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post.save()
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return redirect(post.url)
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If `title` or `body` are missing in the form a special key error will be
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raised which behaves like a :exc:`KeyError` but also a :exc:`BadRequest`
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exception.
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Simple Aborting
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===============
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Sometimes it's convenient to just raise an exception by the error code,
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without importing the exception and looking up the name etc. For this
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purpose there is the :func:`abort` function.
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It can be passed a WSGI application or a status code. If a status code
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is given it's looked up in the list of exceptions from above and will
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raise that exception, if passed a WSGI application it will wrap it in
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a proxy WSGI exception and raise that::
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abort(404)
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abort(Response('Hello World'))
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If you want to use this functionality with custom excetions you can
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create an instance of the aborter class:
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.. autoclass:: Aborter
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Custom Errors
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=============
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As you can see from the list above not all status codes are available as
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errors. Especially redirects and ather non 200 status codes that
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represent do not represent errors are missing. For redirects you can use
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the :func:`redirect` function from the utilities.
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If you want to add an error yourself you can subclass :exc:`HTTPException`::
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from werkzeug.exceptions import HTTPException
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class PaymentRequred(HTTPException):
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code = 402
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description = '<p>Payment required.</p>'
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This is the minimal code you need for your own exception. If you want to
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add more logic to the errors you can override the
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:meth:`~HTTPException.get_description`, :meth:`~HTTPException.get_body`,
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:meth:`~HTTPException.get_headers` and :meth:`~HTTPException.get_response`
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methods. In any case you should have a look at the sourcecode of the
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exceptions module.
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You can override the default description in the constructor with the
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`description` parameter (it's the first argument for all exceptions
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except of the :exc:`MethodNotAllowed` which accepts a list of allowed methods
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as first argument)::
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raise BadRequest('Request failed because X was not present')
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